Self-centering cover for hinged row crop harvesting head

ABSTRACT

A self-centering cover assembly for hinged row crop harvesting head comprises a cover supported on a base member, wherein the base member is positioned by springs to self-center with respect to two hinged sections of the harvesting head.

RELATED APPLICATIONS

This application is related to and claims priority from U.S. ProvisionalPatent Application 61/703,745, which was filed Sep. 20, 2012. Thisapplication is related to U.S. Provisional Patent Applications Nos.61/703,752 and 61/703,740 which were also filed on Sep. 20, 2012.

FIELD OF THE INVENTION

This invention relates to row crop harvesting heads. More particularly,it relates to covers for row crop harvesting heads.

BACKGROUND OF THE INVENTION

Row crop harvesting heads such as corn heads are being manufactured inever increasing widths. Combine harvesters are made larger and morepowerful and capable of carrying larger harvesting heads.

One problem with these larger harvesting heads is their inability toproperly harvest crops planted on undulating terrain. The longerharvesting heads become, the harder it is for them to conform to thesurface of the field.

What is needed, therefore, is an improved row crop harvesting head for acombine harvester that is capable of following undulating terrain in anagricultural field more accurately and capable of harvesting crop moreefficiently with fewer problems of crop fouling or crop damage.

It is an object of this invention to provide such a row crop harvestinghead.

SUMMARY OF THE INVENTION

In accordance with one aspect of the invention, a self-centering coverassembly for row units of a hinged row crop harvesting head, the hingedrow crop harvesting head having a first frame section and a second framesection pivotally coupled together, wherein the self-centering coverassembly comprises: a base member; a cover coupled to the base member; afirst spring coupled between the first frame section and the basemember; and a second spring coupled between the second frame section andthe base member; wherein the first spring and the second spring aredisposed to reposition the cover with respect to both the first framesection and the second frame section when the first frame section andthe second frame section pivot with respect to each other.

The first spring may be coupled to a first row unit on the first framesection, and the second spring may be coupled to a second row unitimmediately adjacent to the first row unit, and the second row unit maybe mounted on the second frame section.

The base member may further comprise guide members that constrain thebase member to slide laterally with respect to the first frame sectionand the second frame section when the first frame section and the secondframe section pivot with respect to each other.

The guide members may be disposed on opposite sides of the base member.

The first spring and the second spring may be serpentine.

The first spring and the second spring may be disposed to extend andretract in a direction generally parallel to a longitudinal extent ofthe hinged row crop harvesting head.

The first spring and the second spring may be fixed to opposite lateralsides of the base member.

The base member may be coupled to the cover by a hinge, and the hingemay constrain the cover to pivot with respect to the base member about alaterally extending axis.

The hinge may be disposed above the first spring and the second spring.

The hinge may be disposed behind the first spring and the second spring.

The base member may be disposed immediately above a pivot axis aboutwhich pivot axis the first frame section, is constrained to pivot withrespect to the second frame section.

The first spring may be disposed on one side of the pivot axis, and thesecond spring may be disposed on the other side of the pivot axis.

The first spring and the second spring may be disposed above the pivotaxis.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevated left side perspective view of a corn head inaccordance with the present invention.

FIG. 2 is a fragmentary elevated left side perspective view of the lefthalf of the corn head of FIG. 1.

FIG. 3 is a depressed rear perspective view of the fragmentary view ofFIG. 2.

FIG. 4A is a fragmentary elevated left side perspective view of the lefthalf of the corn head of FIG. 1 showing two adjacent row units and apoint of FIG. 2 and with the other elements removed.

FIG. 4B is a detailed close-up view of the hinge of FIG. 4A thatsupports the point and cover.

FIG. 5 is a depressed left side rear perspective view of the two rowunits and point of FIGS. 4A and 4B.

FIG. 6 is a slightly depressed right side rear perspective view of thetwo row units and point of FIGS. 4A, 4B and 5.

FIG. 7 is a fragmentary right side rear perspective view of the two rowunits in point of FIGS. 4A, 4B, 5, and 6 with the cover added.

FIG. 8 is an elevated left side perspective view of the corn head ofFIG. 1, showing details of the left side auger joint and the cover ofFIG. 7.

FIG. 9 is a fragmentary elevated left side perspective view of thearrangement of FIG. 8 with the auger tube of the left side auger toillustrate its internal construction.

FIG. 10 is the view of FIG. 9 with a trash seal removed.

FIG. 11 is the view of FIG. 10 with a stub auger tube removed.

FIG. 12 is of FIG. 11 taken at a slightly elevated angle to show thejoint between adjacent auger troughs.

FIG. 13 is a fragmentary elevated right side perspective view of theauger trough of FIG. 12 with the auger removed.

FIG. 14 is a view of the auger troughs and the back walls with the augerremoved taken from approximately the same perspective as FIG. 12.

FIG. 15 is a highly elevated left side rear view of the corn head ofFIGS. 13 and 14 showing the sliding rear wall joint and the rear hingecoupling the left frame section and the center frame section with ahydraulic cylinder and an upper elongate member of the frame of the leftframe section removed for ease of illustration.

FIG. 16 is a cross sectional view of the corn head taken at section lineA-A in FIG. 1. Section line A-A defines a cutting plane that extendsboth vertically and fore-and-aft and is normal to the longitudinalextent of the center frame section.

FIG. 17 is the view of FIG. 16 with a left side row unit arm removed toshow a stalk roll of the row unit immediately adjacent to the pivotaxis.

FIG. 18 is a detail of the view of FIGS. 16-17 showing the center augerand pivot joint between the left frame section and the center framesection.

FIG. 19 is a schematic view of a universal joint that couples driveshafts driving row units in the left frame section and row units in thecenter frame section.

DETAILED DESCRIPTION

Referring to FIG. 1, a corn head 100 is shown having a frame 102 thatextends laterally and generally perpendicular to the direction of travel“V” of the corn head as it travels through the field harvesting crop.

Corn head 100 further comprises a conveyor 104 that extendssubstantially the entire longitudinal extent of the corn head 100 andgenerally perpendicular to the direction of travel of travel “V”.

Corn head 100 further comprises a plurality of row units 101 fixed toframe 102 and extending forward therefrom. In FIG. 1, these row unitsare covered by corresponding points 106 and covers 108 disposed behindthe points 106 that serve to divide the crop into individual rows andfeed the crop into the gap between the arms 170 of adjacent row units101. These row units 101 are seen in greater detail in FIGS. 2-7.

Frame 102 comprises three laterally extending frame sections 110, 112,114 that are pivotally coupled together to permit the three framesections to pivot up and down with respect to each other about a pivotaxis 116 and a pivot axis 118 that extend generally parallel to theground and parallel to the direction of travel “V”.

Frame 102 comprises a left frame section 110, a center frame section112, and a right frame section 114. The left frame section 110 ispivotally coupled to the center frame section 112 to constrain the twoframe sections to pivot with respect to each other about the pivot axis116. The pivot axis 116 extends generally fore-and-aft and parallel tothe direction of travel “V”. Right frame section 114 is pivotallycoupled the center frame section 112 to constrain the two frame sectionsto pivot with respect to each other about the pivot axis 118. The pivotaxis 118 extends generally fore-and-aft and parallel to the direction oftravel “V”. The pivot axis 116 is parallel to the pivot axis 118.

Conveyor 104 is an auger conveyor; it is comprised of three elongateconveyor sections that extend horizontally and perpendicular to thedirection of travel “V”.

The three conveyor sections comprise a left conveyor section 120, acenter conveyor section 122, and a right conveyor section 124. Theconveyor 104 is driven in rotation by at least one motor (not shown).Each of the conveyor sections 120, 122, 124 is comprised of an elongatetube to which a spiral flight is welded. The right (inner) end of theleft conveyor section 120 and the left end of the center conveyorsection 122 are coupled together with a universal joint 130. The left(inner) end of the right conveyor section 124 and the right end of thecenter conveyor section 122 are coupled together with a universal joint132. Universal joints are preferred because they permit the conveyorsections to synchronously rotate about their longitudinal axes beingdriven by motor at one or both ends, while being disposed at an anglewith respect to each other as each of the frame sections pivots withrespect to each other about the pivot axis 116 and the pivot axis 118.

The left conveyor section 120 is supported on a bearing 134 located atan outer end of the left conveyor section 120. The bearing 134 is fixedto the left frame section 110. The bearing 134 supports the outer end ofthe left conveyor section 120 for rotation. The bearing 134 also permitsthe outer end of the left conveyor section 120 to translate with respectto an end wall 137 of the left frame section 110 in a direction parallelto a longitudinal axis of the left conveyor section 120.

As the left frame section 110 pivots downward with respect to centerframe section 112 about the pivot axis 116, the bearing 134 supports theleft conveyor section 120 for rotation, but also permits the leftconveyor section 120 to translate along its rotational axis to the rightwith respect to the left frame section 110.

Likewise, as the left frame section pivots upward with respect to thecenter frame section 112 about the pivot axis 116, the bearing 134permits the left conveyor section 120 to translate along its rotationalaxis to the left with respect to the left frame section 110.

The translating support provided by the bearing 134 to the outer end ofthe left conveyor section 120 therefore eliminates axial stress on theuniversal joint 130 as the left frame section 110 pivots up and down.

The center conveyor section 122 is supported at its left end on abearing 136. The bearing 136 is supported on a bracket 138 that is fixedto and extends forward from the left end of the center frame section112. The center conveyor section 122 is supported at its right end on abearing 140. The bearing 140 is supported on a bracket 142 that is fixedto and extends forward from the right end of the center frame section112. The right conveyor section 124 is supported on a bearing 150 thatsupports the outer end of the right conveyor section 124 for rotation.Bearing 150 is the counterpart of bearing 134 on the other side of thecorn head 100.

Corn head 100 further comprises a generally vertical rear wall 152 thatextends substantially the entire width of the corn head 100. The centerconveyor section 122 provides an aperture 154 in the rear wall 152 topermit the corn head 100 to be supported on a feeder house (not shown)of a combine harvester.

All of the conveyor sections rotate in the same direction. However, dueto the different angles of the auger flights, crop is moved in differentdirections as the conveyor sections rotate. An auger flight 156 that isfixed to an elongate tube 158 of the left conveyor section 120 conveyscrop inwardly toward the center of the corn head 100 from left to right.An auger flight 160 that is fixed to an elongate tube 162 of the rightconveyor section 124 conveys crop inwardly toward the center of the cornhead 100 from right to left. An auger flight 164 is fixed to an elongatetube 166 of the center conveyor section 122 and has two sets of augerflights with opposite twists such that auger flights at opposing ends ofthe center conveyor section 122 convey crop in opposite directionstoward the middle of the center conveyor section 122.

Each of the three frame sections 110, 112, 114 can pivot generallyvertically, both up and down, with respect to its adjacent framesection.

The frame sections 110, 114 on the ends of the corn head 100 can pivotupward with respect to the center frame section 112 as shown by the leftframe section 110, which is pivoted upward with respect to the centerframe section 112 in FIG. 1.

Likewise each frame section can pivot downward with respect to itsadjacent frame section as shown by the right frame section 114 which ispivoted downward with respect to the center frame section 112. The leftframe section 110 and the right frame section 114 can pivot upward 10°above the center frame section 112. The left and right frames sectionscan pivot downward 10° below the center frame section 112.

From here onward in this disclosure, we will only discuss the left halfof the corn head 100. We are doing this for economy of illustration. Thecorn head itself is symmetric about a vertical and fore-and-aft planeextending through the center of the aperture 154. Any explanations madebelow regarding the operation or construction of the left half of thecorn head 100 are equally applicable to the right half of the corn head100, since the left and half and right half are the same, with onedifference: the right half of the corn head 100 is constructed in mirrorimage form to the left half of the corn head 100.

Referring to FIGS. 2-7, the left half of the corn head 100 is shown withseveral of the points 106 and the covers 108 as well as several rowunits 101 removed in order to illustrate the relation between the pointsand covers and row units, as well as the frame members that supportthese portions of the corn head 100. Two of the row units 101,identified below as 101A and 101B, are disposed immediately adjacent toeach other on opposite sides of the pivot axis 116. They are identicalin all respects to the other 22 row units of corn head 100 that are notall individually illustrated in this document.

The left frame section 110 and the center frame section 112 eachcomprise an elongate toolbar 168 to which row units 101 are attached.The elongate toolbars 168 extend generally perpendicular to thedirection of travel “V” and extend parallel to the ground. Each of therow units 101 includes two forwardly extending arms 170 that are mountedon and extend forward from a row unit gearbox 178. A gathering chain 174is disposed on top of each of the arms 170. Each row unit 101 has twostalk rolls 176, with each stalk roll 176 disposed side by side,partially underneath and between each of the arms 170.

The stalk rolls extend forward from and are driven in rotation by therow unit gearbox 178 disposed at the rear of the row unit 101. The rowunit gearbox 178 is fixed to the elongate toolbar 168 and the arms 170,the gathering chains 174, and the stalk rolls 176 are cantileveredforward from the row unit gearbox 178 and the elongate toolbar 168.

The left frame section 110 and the center frame section 112 includeelongate frame members 180 disposed behind and generally parallel to theelongate toolbars 168. The elongate frame members 180 and the elongatetoolbars 168 are fixed together with struts 181 that extendfore-and-aft. The struts 181 are fixed at their front ends to theelongate toolbars 168 and at their rear ends to the elongate framemembers 180. The struts 181 hold the elongate toolbars 168 and theelongate frame members 130 in fixed positions with respect to eachother.

The left frame section 110 and the center frame section 112 also includeelongate upper frame members 182 disposed along the top portion of cornhead 100.

The left frame section 110 and the center frame section 112 also includevertical frame members 184 that extend between and are fixed to theirrespective elongate frame members 180 and elongate upper frame members182.

A forward hinge 186 is fixed to and extends between adjacent ends of theelongate toolbars 168 on the left frame section 110 and the center framesection 112. A rear hinge 188 is fixed to and between adjacent ends ofelongate frame members 180 on the left frame section 110 and the centerframe section 112. The forward hinge 186 and the rear hinge 188 definethe pivot axis 116 between the left frame section 110 and the centerframe section 112.

The hinges are located relative to each other such that the pivot axis116 extends for-and-aft and generally horizontally. While the pivot axis116 is generally horizontal, it does have a slightly downward slope asit extends forward. The pivot axis 116 passes between the two adjacentrow units 101 (identified as row unit 101A and row unit 101B) that aredisposed on the right end of the left frame section 110 and the left endof the center frame section 112, respectively.

The row unit 101A is fixed to the elongate toolbar 168 of the left framesection 110. Row unit 101B is fixed to the elongate toolbar 168 of thecenter frame section 112.

As the left frame section 110 and the center frame section 112 pivotwith respect to each other, the row unit 101A and the row unit 101B(which are disposed slightly above the elongate toolbars 168) will alsomove with respect to each other. The upper rear portions of the rowunits 101A and 101B will move closer together as the left frame section110 pivots upward with respect to the center section, and will movefarther apart as the left frame section 110 pivots downward with respectto the center frame section 112. For this reason, the point 106 and thecover 108 that bridge the gap between the left frame section 110 and thecenter frame section 112 are spring mounted.

In FIGS. 4A and 4B a point 106 covers a gap between two adjacent ones ofthe row units 101A and 101B, and hence covers a gap between the leftframe section 110 and the center frame section 112. A cover 108 (notshown in FIGS. 4A and 4B, but shown in FIGS. 1, 2, 3, and 7, also coversthe gap between the two row units 101A and 101B and hints covers a gapbetween the left frame section 110 and the center frame section 112.

The cover 108 (shown in FIGS. 1, 2, 3, and 7) that would normally bedisposed immediately behind the point 106 has been removed in FIGS. 4Aand 4B for purposes of illustration, in order to show the structures formaintaining the proper alignment of the point 106 and the cover 108 overthe gap between the two row units 101A and 101B. The point 106 ispivotally connected to the cover 108 at two pivot points 190, 192disposed on either side of the point 106. This permits the point 106 topivot up and down with respect to the cover 108. The cover 108 is fixedto pivot pins 193, 194 that are disposed at the back of the row units101A, 101B. Pivot pins 193, 194 are embedded in the plastic matrix ofthe cover 108, and are pivotally coupled to hinge 196. Hinge 196comprises a base member 198 that extends laterally between the twoadjacent row units 101A and 101B. Two vertical members 200, 202 extendupward from this base member 198. The upper ends of vertical members200, 202 are pivotally coupled to pivot pins 193, 194. This hingearrangement constrains the cover 108 to pivot with respect to the rowunits 101A, 101B about an axis 204 which extends laterally and generallyparallel to the elongate toolbars 168 and to the longitudinal extent ofthe corn head 100.

In order to permit the row units 101A, 101B to move closer together andfarther apart as the left frame section 110 pivots up and down withrespect to the center frame section 112, a left spring 206, and a rightspring 208 are coupled to the left side in the right side of the basemember 198 of the hinge 196. The left spring 206 is also fixed to theright side of the row unit 101A. The right spring 208 is also fixed tothe left side of row unit 101B. In this manner, the hinge 196 issupported on both row units and extends across the gap between the leftframe section 110 and the center frame section 112.

The left spring 206 and the right spring 208 are extension springs. Theyare made of a thin, flexible, flat plate that is formed into aserpentine such that the springs can be extended and retracted in adirection generally parallel to the longitudinal extent of the elongatetoolbars 168. The left spring 206 and the right spring 208 aresubstantially the same, and have the same spring constant. Therefore,when the two adjacent row units 101A, 101B separate from each other ormove closer together, the left spring 206 and the right spring 208 causethe hinge to self-center between the two adjacent row units 101A, 101B.The left spring 206 and the right spring 208 could be compressionsprings or extension springs.

The cover 108 self-centers because the force the springs apply toadjacent ones of the row units 101A, 101B and to the cover 108 is causesthe hinge 196 to move to a position between the two row units 101A, 101Bin which the tension in each spring is equal 9 i.e. there is no netforce pulling the hinge 196 to one side or another. Since the springconstants of each spring are the same this automatically moves the hinge196 to a position right in the center of the two row units no matterwhat their relative spacing is.

The serpentine form of the left spring 206 and the right spring 208provides additional benefits. They substantially eliminate anyfore-and-aft movement of the point 106 and the cover 108. Furthermorethey substantially eliminate rotation of the point 106 and cover about avertical axis. This helps prevent the point 106 from being deflectedside to side.

By themselves, the left spring 206 and the right spring 208 do notsubstantially prevent movement of the hinge 196 up and down with respectto the two row units, however. For this reason, portions of the basemember 198 of hinge 196 extend on top of the adjacent row units 101A,101B. These portions of the base member 198 are shown here as the lefttab 210 and the right tab 212. These two tabs are disposed abovestructural members of the two row units. They are positioned so that theweight of the hinge 196, and hence at least a portion of the weight ofthe cover 108 rest upon the adjacent row units. In this manner, thehinges are not under a constant stress due to supporting the entireweight of the hinge 196 and the cover 108.

The left tab 210 and the right tab 212 are not fixed rigidly to the rowunits. Instead, the left tab 210 and the right tab 212 extend laterallyaway from opposite sides of base member 198 and extend over the top ofthe surface of the adjacent row units to rest thereon.

The left tab 210 and the right tab 212 are constrained to assist inpreventing the point 106 from being deflected side to side as it engagescrop. The left tab 210 and the right tab 212 function as guide membersthat slide laterally with respect to the two adjacent row units betweensurfaces on each side of the row unit that constrain the tabs fromtranslating fore-and-aft with respect to the row units. The left tab 210has a forward facing surface 214 that is immediately adjacent to arearward facing surface 216 of row unit 101A. The left tab 210 has arearward facing surface 218 that is immediately adjacent to a forwardfacing surface 220 of row unit 101A. The right tab 212 has a forwardfacing surface 222 that is immediately adjacent to a rearward facingsurface 224 of row unit 101B. The right tab 212 has a rearward facingsurface 226 that is immediately adjacent to forward facing surface 228of row unit 101B. These surfaces constrain the base member 198 toside-to-side (i.e. lateral) movement, and prevent it from rotating abouta generally vertical axis, at least as long as the tabs are resting onthe surface of the adjacent row units and are therefore disposed betweenthe forward and rearward facing surfaces of the row units.

When the point 106 is deflected side to side, the left spring 206 andthe right spring 208 will resist this deflection. The adjacent surfacesdescribed above on the row units 101A, 101B and on the left tab 210 andthe right tab 212 also resist or prevent this lateral movement byengaging each other end whenever the deflection force tries to twist thepoint 106 to one side or the other.

FIGS. 5 and 6 illustrate the rear of the row units 101A and 101B thatare supported on the left frame section 110 and the center frame section112, respectively. The row unit 101A is driven by a drive shaft 211 thatis shown in FIG. 6 extending slightly out of the row unit gearbox 178 ofthe row unit 101A. The drive shaft 211 has a rotational axis 213 thatextends longitudinally. Row unit 101B is driven by drive shaft 215,which is shown extending slightly out of the row unit gearbox 178 of therow unit 101B. Drive shaft 215 has a rotational axis 217 that extendslongitudinally.

All the row units 101 on the left frame section 110 are driven by driveshaft 211, which extends in a straight line through each of the rowunits. All the row units 101 on the center frame section 110 are drivenby drive shaft 215, which extends in a straight line through each of therow units. Both drive shafts have a non-circular, regular polygonalouter surface, preferably a regular hexagon or octagon in cross section.

The two drive shafts 211, 215, if extended along their respectiverotational axes 213, 217, will intersect each other in the space betweenthe row units 101A and 101B in all possible pivotal positions achievableby the left frame section 110 with respect to the center frame section112.

Furthermore, both drive shafts will intersect the pivot axis 116. In apreferred embodiment, the rotational axis 213 and the rotational axis217 both intersect the pivot axis 116. This has the advantage ofpermitting both drive shafts to be coupled together with a universaljoint 300 (FIG. 19). In FIG. 19, this relationship is illustrated in analternative embodiment that shows a universal joint 219 coupling driveshafts 211 and 215. In FIG. 19, rotational axis 213 and the rotationalaxis 217 both intersect the pivot axis 116. Furthermore, the projectedenvelope 211X of drive shaft 211 intersects the projected envelope 215Xof drive shaft 215. The envelopes of the drive shafts are projectedparallel to the rotational axis 213 and the rotational axis 217.

When the left frame section 110 pivots upward with respect to the centerframe section 112, drive shaft 211 assumes the position 211B. When theleft frame section 110 pivots downward with respect to the center framesection 112, drive shaft 211 assumes the position 211A. In each of thesealternative positions of drive shaft 211, and in all of the intermediatepositions for lesser pivoting of drive shaft 211, the rotational axis213 will intersect the rotational axis 217 at the pivot axis 116.Furthermore, the projected envelopes 215X of the drive shaft 215 and theprojected envelope 211BX of drive shaft 211 in the position 211B and theprojected envelope 211AX of drive shaft 211 in the position 211A willintersect each other and will intersect the pivot axis 116.

With the drive shafts 211, 215 so arranged to intersect the pivot axis116, the axial loads on the universal joint 219 will be minimizedthroughout the entire range of pivotal movement of the left framesection 110 with respect to the center frame section 112.

FIGS. 8-12 illustrate an arrangement for coupling the left and centerconveyor sections together. FIG. 8 shows the complete assembly of theleft conveyor section 120 and the center conveyor section 122. In FIG.9, the elongate tube 158 for the left conveyor section 120 has beenremoved, exposing a first yoke 240 of the universal joint 130. The firstyoke 240 is supported on a shaft 242 that in turn is fixed to aplurality of spaced apart circular disks 244. Circular disks 244 arewelded to the inside surface of the elongate tube 158. In this manner,the first yoke 240 is fixed to the elongate tube 158 and is disposedsubstantially entirely inside the end of the elongate tube 158. The free(right) end of the elongate tube 158 is disposed immediately adjacent toa seal 246.

Seal 246 has an outer diameter that is substantially the same size asthe outer diameter of the elongate tube 158. It is slightly smaller thanthe elongate tube 158, and therefore the elongate tube 158 can extendclosely around the outside of seal 246, as shown in FIG. 8. Seal 246 isgenerally disk shaped extends inwardly from its outer edge to an innerperiphery that is disposed very closely to the contours of the firstyoke 240 and the second yoke 250. The first yoke 240 is coupled to across-shaped connecting element 248 that forms a part of the universaljoint 130, which in turn is coupled to the second yoke 250 that formsthe final part of the universal joint 130. The inner periphery of seal246 is spaced a small distance apart from the first yoke 240 and thesecond yoke 250 and the cross-shaped connecting element 248. Thefunction of seal 246 is to prevent the plant matter being conveyed bythe conveyor 104 from being jammed into the universal joint 130,damaging the bearing 136, and winding around the elongate tubes thatform part of the conveyor 104. When this occurs, a mass of plant matterforms that effectively blocks the conveyor. The agricultural harvestermust be stopped, the conveyor must be stopped, the operator must get outof the cab, climb down, and clear the plant matter wrapped around theconveyor 104. This can significantly delay harvesting.

Seal 246 is fixed to a stub tube 252 which surrounds the second yoke250. The second yoke 250, in turn, is fixed to and rotates with the leftend of the center conveyor section 122. The second yoke 250 is disposedon the left side of the bearing 136. It is spaced to the left (outer)side of the bearing 136 a distance roughly equal to the diameter of theelongate tube 158 and the elongate tube 166. This spacing provides azone of separation between the bearing 136 and seal 246. The stub tube252 has an outer diameter that is substantially equal to the outerdiameter of the elongate tube 158.

This similarity in diameter permits plant material to slide smoothlyfrom the elongate tube 158 to the stub tube 252, and thence past thebearing 136, to the elongate tube 166 of the center conveyor section122, which also has an outer diameter that is substantially equal to theouter diameter of the elongate tube 158.

In FIG. 8, the auger flight 156 of the left conveyor section 120 isshown extending axially inwardly past the end of the elongate tube 158and over the top of the stub tube 252. In an alternative and preferredembodiment, the auger flight 156 can be terminated at the end of theelongate tube 158. This shortened length of the auger flight 156 isshown as a dashed line in FIG. 8.

The stub tube 252 has its own auger flight 254. The auger flight 254 isangularly disposed between 5 and 30 degrees behind the auger flight 156of the left conveyor section 120 as the tubes rotate. This reduces thepossibility that material will become trapped between the two flightsand wrap around the elongate tube 158 and the elongate tube 166. Stubtube 252 terminates at the bracket 138.

Since the bearing 136 is spaced away from the second yoke 250 of theuniversal joint 130, the auger flight 254 at the end of the centerconveyor section 122 can be disposed immediately adjacent to the augerflight 156 at the end of the left conveyor section 120. The auger flight254 and the auger flight 156 can be so close they overlap each otherwhen the left frame section 110 is pivoted up and down with respect tothe center frame section 112. By providing an auger flight 254 on a stubportion of the center conveyor section 122 the universal joint 130 canbe cantilevered out away from the bracket 138 and the flight-to-flightspacing of the two conveyor. sections made smaller. This is enhanced bylocating the end of the auger flight 254 angularly away from theadjacent end of the auger flight 156, which prevents the flights fromphysically interfering with each other even when they overlap duringtimes of extreme pivoting of one frame with respect to the other.

FIGS. 12-15 illustrate two further features of the corn head 100. Eachsection of the auger rotates above a trough formed by a long concavesheet metal form. The auger troughs are supported on the frames of eachframe section. Just as the auger has joints that permit the auger topivot when the frame members are pivoted with respect to each other, soalso the trough has a pivot joint 260 as well. The pivot joint 260, asbest shown in FIG. 12, is disposed immediately below the universal joint130. The pivot joint 260 is disposed between the universal joint 130 andthe pivot axis 116.

As best shown in FIG. 13, the pivot joint 260 is also disposedimmediately above the pivot axis 116 and lies in the same vertical planeas the pivot axis 116. The pivot joint 260 forms a junction between aleft auger trough 262 disposed underneath the left conveyor section 120,and a center auger trough 264 disposed underneath the center conveyorsection 122.

The left auger trough 262 extends substantially the entire length of theleft frame section 110 underneath the left conveyor section 120. Thecenter auger trough 264 extends substantially the entire length of thecenter frame section 112 underneath the center conveyor section 122.

The left end of the center auger trough 264 is disposed such that itextends underneath the right end of the left auger trough 262. In thearrangement shown herein, an auger trough extension 266 is removablyfixed to the left end portion of the center auger trough 264 and extendsfarther to the left and underneath the left auger trough 262. The augertrough extension 266 is preferably made out of a flexible, wearresistant material. Its short length makes it easier to remove in thecase of wear. The overlapping of the left auger trough 262 on top of thecenter auger trough 264 (including on top of the auger trough extension266 of the center auger trough 264) ensures that crop pulled leftwardtoward the center of the corn head 100 will slide easily over theseshingled auger troughs. In the preferred arrangement, the left augertrough 262 and the center auger trough 264 (including the auger troughextension 266) preferably are in sliding contact with each other, or, ifnot in sliding contact, are spaced apart a distance of no more thanabout 5 mm over the width of the troughs.

FIGS. 14 and 15 illustrate a similar overlapping arrangement that joinsthe left frame section back wall 270 to the center frame section backwall 272. The back walls 270, 272 are generally vertical sheets of metalfixed to the frame 102. The back walls form a barrier to prevent cropfrom being pushed through the back of the corn head 100 when theconveyor 104 rotates.

In the illustrated arrangement, the left frame section back wall 270lies on top of (is forward of) the center frame section back wall 272where the two overlap.

When a hydraulic cylinder 274 extends and retracts, it causes theelongate upper frame member 182 of the left frame section 110 and theelongate upper frame member 182 of the center frame section 112 to bedrawn toward each other or pulled away from each other. This causes theleft frame section 110 to pivot up and down with respect to the rightframe section 112. It also causes the center frame section back wall 272to slide with respect to the left frame section back wall 270. As withthe auger trough arrangement, this overlapping of left back wall overcenter back wall ensures that crop flow will transition smoothly fromthe left frame section 110 to the center frame section 112 withoutgetting caught.

In a preferred arrangement, the left frame section back wall and thecenter frame section back wall are in sliding contact with each otheror, if not in sliding contact, are spaced apart a distance of no morethan about 5 mm over the height of the back wall.

FIGS. 16, 17 and 18, particularly illustrate the orientation andlocation of the forward hinge 186 and rear hinge 188. These figures arecross-sectional views taken by a cutting plane that extends bothvertically and fore-and-aft. This cutting plane passes through theuniversal joint 130 and the forward hinge 186 and the rear hinge 188.The hinges define the pivot axis 116 about which the left frame section110 pivots with respect to the center frame section 112.

The pivot axis 116 extends through pivot pins of the forward hinge 186and the rear hinge 188, forward and downward. In the side view of FIGS.16-18, the pivot axis 116 passes through a skid shoe 276 disposed on aforward end of arm 170. In the side view of FIGS. 16-18, the pivot axis116 also passes through the stalk rolls 176.

What this location of the pivot axis 116 means from a kinematicperspective is that as the left frame section 110 pivots up and downwith respect to the center frame section 112, the spacing betweenadjacent row units on the left frame section 110 and the center framesection 112 changes as little as possible for each pivot.

If the left frame section 110 was positioned in FIGS. 16-17 with a pivotangle of zero degrees with respect to the center frame section 112 (i.e.when the corn head 100 rests on flat ground), the pivot axis 116 wouldbe located directly between the adjacent row units 101: between arms 170of adjacent ones of the row units 101A, 101B, between the stalk rolls176 of adjacent row units 101A, 101B, and between skid shoes of adjacentrow units 101A, 101B.

Because of this spatial relationship, as the corn head 100 travelsthrough the field, with the left frame section 110 pivoting up and downwith respect to the right frame section 112, this pivoting does notsubstantially change the lateral spacing between the adjacent row unitsat the skid shoes and stalk rolls of those adjacent row units. Thus, asthe left frame section 110 and the right frame section 114 pivot up anddown, the relative spacing between adjacent row units does not change,but stays constant. This is important since adjacent rows of crops areplanted with a constant relative spacing whether the terrain is rollingor flat. If (in an extreme example) the pivot axis 116 extendedfore-and-aft but was 6 feet above the row units, the spacing betweenadjacent row units could change as much as 20-40 centimeters every timethe left frame section 110 pivoted 10 degrees with respect to the centerframe section 112. This sudden additional spacing between adjacent rowunits would cause a significant portion of the crop to be crushed ratherthan harvested as the points ran over rows of crop rather than feedingthem between the stalk rolls.

The universal joint 130 also lies in the same vertically andfore-and-aft extending plane as the pivot axis 116. The universal joint130 is therefore directly above the pivot axis 116.

The joint 160 defined between the left auger trough 262 and the centerauger trough 264 intersects the same plane as the universal joint 130and the pivot axis 116. Thus, portions of the left auger trough 262 andthe center auger trough 264 pass through the vertical and fore-and-aftextending plane. The pivot axis 116 is directly below the joint 160.This close spacing of the auger troughs to the pivot axis 116 permitsthe pivot joint 260 to be made quite narrow and to seal well.

The invention claimed is:
 1. A self-centering cover assembly for rowunits (101) of a hinged row crop harvesting head (100), the hinged rowcrop harvesting head (100) having a first frame section (110, 114) and asecond frame section (112) pivotally coupled together, theself-centering cover assembly comprising: a base member (198); a cover(108) coupled to the base member (198); a first spring (206, 208)coupled between the first frame section (110, 114) and the base member(198); and a second spring (206, 208) coupled between the second framesection (112) and the base member (198); wherein the first spring (206,208) and the second spring (206, 208) are disposed to reposition thecover (108) with respect to both the first frame section (110, 114) andthe second frame section (112) when the first frame section (110, 114)and the second frame section (112) pivot with respect to each other. 2.The self-centering cover assembly of claim 1, wherein the first spring(206, 208) is coupled to a first row unit (101) on the first framesection (110, 114), and wherein the second spring (206, 208) is coupledto a second row unit (101) immediately adjacent to the first row unit(101), and wherein the second row unit (101) is mounted on the secondframe section (112).
 3. The self-centering cover assembly of claim 1,wherein the base member (198) further comprises guide members (210, 212)that constrain the base member (198) to slide laterally with respect tothe first frame section (110, 114) and the second frame section (112)when the first frame section (110, 114) and the second frame section(112) pivot with respect to each other.
 4. The self-centering coverassembly of claim 3, the guide members (210, 212) are disposed onopposite sides of the base member (198).
 5. The self-centering coverassembly of claim 1, wherein the first spring (206, 208) and the secondspring (206, 208) are serpentine.
 6. The self-centering cover assemblyof claim 1, wherein the first spring (206, 208) and the second spring(206, 208) are disposed to extend and retract in a direction generallyparallel to a longitudinal extent of the hinged row crop harvesting head(100).
 7. The self-centering cover assembly of claim 1, wherein thefirst spring (206, 208) and the second spring (206, 208) are fixed toopposite lateral sides of the base member (198).
 8. The self-centeringcover assembly of claim 1, wherein the base member (198) is coupled tothe cover (108) by a hinge (196), wherein the hinge (196) constrains thecover (108) to pivot with respect to the base member (196) about alaterally extending axis (204).
 9. The self-centering cover assembly ofclaim 8, wherein the hinge (196) is disposed above the first spring(206, 208) and the second spring (206, 208).
 10. The self-centeringcover assembly of claim 9, wherein the hinge (196) is disposed behindthe first spring (206, 208) and the second spring (206, 208).
 11. Theself-centering cover assembly of claim 1, wherein the base member (198)is disposed immediately above a pivot axis (116, 118) about which pivotaxis the first frame section (110, 114) is constrained to pivot withrespect to the second frame section (112).
 12. The self-centering coverassembly of claim 11, wherein the first spring (206, 208) is disposed onone side of the pivot axis (116, 118), and wherein the second spring(206, 208) is disposed on the other side of the pivot axis (116, 118).13. The self-centering cover assembly of claim 12, wherein the firstspring (206, 208) and the second spring (206, 208) are disposed abovethe pivot axis (116, 118).